Backfire release



Jan. 26, 19317., .D.-L. WERTZ' 2,068,722

BACKFIRE RELEASE Filed Jail. 28, 1932 g I INVENTOR h BY Dwpel/L,-wmz 1 I ATTORNEY Patented Jan. 26, 1937 UNITED STATES PATENT OFFICE Machine Compa y, Elmira,

tion of New York N. Y., a. corpora- Application January 28, 1932, Serial No. 589,517

8Claims.

This invention relates to a backfire release for automatic starting mechanism and more particularly to a device for preventing actuation of an automatic starting mechanism during backward rotation of the engine to be started.

Automatic starting mechanisms have heretofore been constructed embodying various devices for preventing actuation oi. the starting mechanism when the engine is running and causing 10 actuation thereof when the engine stops; but these devices have generally been inoperative to prevent actuation of the starting motor when the engine is rotating backward as in case of a backfire. It will be readily appreciated that the operation of the starting mechanism under such circumstances throws heavy stresses on the starting elements which it would be desirable to avoid.

It is an object of the present invention to provide a novel device for rendering an automatic starting mechanism inoperative to start an engine during backward rotation thereof.

It is another object to provide such a device which is arranged to prevent'reoperation of the automatic starting mechanism after a back- 2 fire, until the operator has again placed the automatic starting mechanism in active condi- A further object is to provide such a device in which the control elements of the automatic 30 starting mechanism are operated in consequence of backward rotation of the engine to render the automatic starting mechanism inoperative.

Another object is to provide such a device which may be made as an attachment to an automatic 35 starting mechanism without expensive alteration thereof. a

Further objects and advantages will be apparant to those skilled in this art from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a semi-diagrammatic illustration of one preferred embodiment of the invention, the parts being shown in their normal idle position;

Fig. 2 is a similar view of a second embodiment of the invention; and

Fig. 3 is a detail partly in section of a third embodiment of the invention.

Referring first to Fig. 1 of the drawing, there is illustrated an electrical system for an internal combustion engine, not shown, comprising a battery I, grounded at 2, and connected by a lead 3 to a magnetically operated starting switch 4-. Switch 4 is connected by leads 5 and 8 to a starting motor'SM which is grounded at I to complete 56 the starting circuit.

The starting switch is operated by a solenoid 8 which is energized by a control circuit including battery I, leads 3 and 4', manual switch 5', leads 6' and I, stationary contact 9 and movable contact III which is mounted on a spring strip i I 5 grounded, as indicated at 12. Manual switch 5' may, if desired, be arranged to control the ignition system of the engine as indicated on the drawing.

Means are provided for opening contacts 9, H)

, 10 when the engine starts in order to deenergize the solenoid 8 and allow the starting switch 4 to open.

As here illustrated, this means comprises a lever I3 pivoted at l4 and actuated by a solenoid plunger I5 to engage the end of the spring strip Ii and move contact i0 away from contact 9. Plunger l5 is actuated by two coils l6 and i1. Coil I6 is connected by a lead l8 to the dead side of the starting switch 4 and is grounded at l9; and coil I1 is connected to an engine-driven generator G by a lead 2|, and is also grounded at iii. The function of the coil I6 is to move the lever l3 to open contacts 9, l0 when the engine starts, and the function of coil I1 is to retain said contacts open as long as the engine is in operation.

According to the present invention, independent means are provided ioropening the contacts 9, I0 responsive to backward rotation oi the engine and for holding said contacts open under the control of the operator. As here illustrated, this means comprises a slidable magnetic plunger 22 which is arranged to operate a lever 23, the free end of which lever carries a pin 3|. Pin 3| is adapted to engage and bend back the spring strip Ii, carrying the movable contact l0 away from fixed contact 9, upon actuation of the plunger 22. Plunger 22 is actuated by a coil 24 connected at one end by a lead 25 to the lead 6' of the control circuit, and connected at the other end by a lead 26 to the plunger 22. Plunger 22 is insulatedirom its bearing elements as indicated at 2B, and lever 23 is insulated as indicated at 29 whereby the circuit of the'magnet 24 is normally open. Initial mo- 45 tion of the plunger 22,'however, causes the pin 3| to'engage the spring strip I I, which completes the circuit of coil 24 to the ground [2 whereby said coil is energized to further actuate the plunger 22 and retain the contact iii in its open position until the circuit of the magnet 24 is broken at the manual switch 5'.

Initial actuation of the plunger 22 in response to the backward rotation oLthe engine is etiected, as illustrated, by means 0! a pressurener.

responsive element such as a flexible diaphragm 32 mounted within a chamber formed by a casing element 33. This chamber is connected by means of a conduit 34 with an element of the fuel intake system of the engine such as the intake manifold indicated at 35. Plunger 22 is fixed at one end to the center of diaphragm 32, while insulated therefrom as indicated at 21. Pressure in the intake manifold will thus cause the diaphragm 32 to movesaid plunger to engage the pin II with the spring strip II and complete the ground connection for coil 24.

In the operation of the device, starting with the parts in the positions illustrated in Fig. 1 closure of the manual switch 5' closes the control circuit, causing energization of the solenoid 8 and consequent closure of the starting switch 4, whereby the starting motor is energized to crank the engine. When the engine starts, the plunger I 5 is actuated by the coil l6 to open contacts 8, II, and the generator coil ll retains said contacts open as long as the engine is in operation.

Should the engine backfire, however, the generator is inoperative to energize the coil l1, and the contacts 8, I. would automatically be allowed to close. However, backward rotation of theenginecausespressuretobebuiltupinthe intake manifold 35, which pressure is transmitted through the conduit 34 to the chamber 33 and causes the diaphragm 32 to move the plunger 22 suiiiciently to "cause the pin II on lever 23 to engage the spring strip II. The consequent energization of coil 24 causes the plunger 22 to bend back the spring strip l I, opening contacts 9, l0 and retaining the same in open position.

When backward rotation of the engine has ceased, the operator need only open the manual switch 5v to deenergize the coil 24, whereupon reclosure of the starting switch causes the starting operation to be repeated in the usual man- In the embodiment of the invention illustrated in Fig. 2 the elements of the starting system and of the automatic starting mechanism are the same as illustrated in Fig. l and are similarly numbered, but a somewhat different arrangement with respect to the backfire releasing mechanism is provided. As here illustrated,- a dia phragm 26 which is subjected to pressure in the fuel intake system in thev same manner as the diaphragm I2, is arranged to operate a lever 31. Lever 31 is fnlcrumed at 38 and is pivoted at its free end" to a link 4|. Link H is provided with a shoulder-42 arranged to engage the spring strip II and thereby move contact l0 out of engagement with contact 9.

In order to retain the contacts 9, I 0 open, link 4| is provided with retaining means here shown in the form of a magnetic latch 43 arranged to engage in a notch 44 in said link. Latch 43 is normally retained in its disengaged position by means of a spring 45 but is adapted to be moved into engagement with the link H by means of a coil 46, one end of which is adapted to be connected by a lead 41 to the lead 6' of the control circuit, and the other of which is connected to a brush 48. Initial movement of the link 4| causes a conducting section 49 thereof to engage the brush 48 and a grounding brush 5!! whereby the circuit of coil 46 is completed. When the notch 44 is moved into registry with latch 43, the latch will therefore engage therein and retain contacts 8, ll! open imtil the magnetic circuit is broken by opening of the manual switch 5.'

The operation of this embodiment of the invention is substantially similar to that previously described except that the opening of the contacts 9, I0 is efiected directly by the force of the intake pressure on the diaphragm 3B, and the latch 43 and coil 46 merely serve as retaining means to prevent reactuation oi the starting mechanism until the manual switch 5 has been opened and reclosed.

In the embodiment illustrated in Fig. 3, the diaphragm 5] which corresponds to diaphragm 32 in Fig. 1 is provided with a grounding contact 52 which is normally adjacent a contact 53 mounted on one end of a magnet core 54 but insulated therefrom as indicated at 55. Core 54 is arranged to be energized by a coil 56, one end of which is connected to contact 53 by -a lead 51. The opposite end of coil 56 is connected by a lead 58 t0 the manual switch 5' in the same manner as coils 24 and 45 in the previous embodiments of the invention. Contacts 52 and 53 are formed of magnetic material whereby magnetization of core 54 by coil 58 causes contact 52 to be held up against contact 53 on the end of the core 54, thus maintaining the ground connection for the coil 58 whereby said coil re- .mains energized after the intake pressure has been withdrawn from the diaphragm 5| until the manual switch 5' has been opened to break the circuit of coil 56.

The opposite end of core 54 extends within a short distance of the upper end of spring strip l I on which is mounted,.a weight member59 of magnetic material. Energization of coil 56 causes said weight member to be drawn over against the end of'core 54, thus opening contacts 9, III and preventing closure of the starting switch.

In the operation of this embodiment of the invention, backward rotation of the engine causes pressure in the intake system which causes diaphragm 5i to move contact 52 into engagement with contact 53, thus completing the ground connection for coil 56. If the ignition switch 5' is closed at this time, the coil 56 is energized, thereby opening contacts 9, ill and preventing actuation of the starting mechanism until the ignition switch 5' is opened and reclosed.

It will be understood that since the spring strip ii will vibrate upon release thereof after deflection, a time delay will be introduced thereby which will prevent the effective energization of the control circuit for a predetermined time after such release. Such time delay is desirable in order to permit the engine to come to rest, since backfiring may under certain circumstances con tinue until the ignition switch is opened, and

if the ignition switch were immedately reclosed, actuation of the starting mechanism might take place while the engine was still rotating back- 'ward if it were not for this time delay.

Although certain embodiments of the invention have been shown and described in detail, it will be understood that various other embodiments are possible and various changes may be made in the construction and arrangements of the elements without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In combination with an engine to be started having a fuel intake system, automatic starting mechanism including a magnetic starting switch, a control circuit therefor including a pair of contacts, means responsive to forward rotation of ISO the engine for opening said contacts, and means for opening said contacts responsive to positive pressure in said fuel intake system due to backward rotation of the engine.

2. In combination with an engine to be started having a fuel intakesystem, automatic starting mechanism therefor including a magnetic starting switch, a control circuit therefor includinghaving a fuel intake system, automatic starting mechanism therefor including a magnetic starting switch, a control circuit therefor including a pair of contacts, means responsive to forward rotation' of the engine for opening said contacts, a pressure-responsive element, means connecting said element to the fuel intake system of the engine whereby variations in pressure therein will move said element, and means whereby motionof said element responsive to positive pressure in said system causes said contacts to be opened.

' 4. In combination with an engine to be started having a fuel intake system, automatic starting mechanism therefor including a magnetic starting switch, a control circuit therefor including a pair of contacts, means responsive to forward rotation of the engine for opening said contacts, a pressure-responsive element, means'bonnecting said element to the fuel intake system of the engine whereby variations in pressure therein will move said element, means whereby motion of said element responsive to positive pressure in saidsystem causes said contacts to be opened, and manually controlled means energized by such motion for holding said contacts open.

5. Incombination with anengine to be started having a fuel intake system, automatic starting mechanism therefor including a magnetic starting switch, a control circuit therefor including a manual switch and a pair of contacts, means responsive to forward rotation of the engine for opening said contacts, a, pressure-responsive element, means connecting said element to the fuel intake systemof the engine whereby variations in pressure therein will move said element, means whereby motion of said element responsive to positive pressure in said system causes said contacts to be opened, and a holding circuit for said contacts including said manual switch and a solenoid, said solenoid acting to supplement the action of the pressure-responsive element in opening and holding open said contacts.

6. In combination with an engine to be started having a fuel intake system, automatic starting mechanism therefor including a magnetic start ing switch, a control circuit therefor including a manual switch and a pair of, contacts, means responsive to forward rotation of the engine for opening said contacts, a pressure-responsive element, means connecting said element to the fuel intake system of the engine whereby variations in pressure therein will. move said element, means whereby motion of said element responsive to positive pressure in said system causes said contacts to be opened, a holding circuit for said,

contacts including said manual switch and a solenoid, said solenoid acting to supplement the action of the pressure-responsive element in.

opening and holding open said contacts,- and means responsive to initial movement of the pressure-responsive member to close said holding circuit.

'7. In combination with an engine to be started having a fuel intake system, automatic starting mechanism for the engine including a magnetic starting switch, a control circuit therefor including a set of contacts, an element movable by positive pressure above atmospheric, in the fuel intake system, means connecting said element with one of said contacts whereby said motion of the. element is transmitted thereto to open said contacts, and means for delaying effective closure of said contacts for a predetermined time after the dissipation of said positive pressure in the intake system.

8. In combination with an engine to be started having a fuel intake system, automatic starting mechanism for the engine including a magnetic starting switch, a control circuit therefor including a set of contacts, an element movable by positive pressure above atmospheric, in the fuel intake system, means connecting said element with one of said contacts whereby said motion of the element is transmitted thereto to open said contacts, and means for vibrating said contact for a predetermined time after release thereof.

DANIEL L. WERTZ. 

